1. Field of the Invention
The invention relates to a control and regulating device for a hydrostatic drive assembly of the type including adjustable pump driven by a primary power source and by which several consumers of hydrostatic energy are acted upon, and having a nominal speed value pickup provided for each consumer and an adjustable restrictor assigned to each consumer. The invention also relates to a process for operating such a control and regulating device.
2. Description of the Art
A familiar control and regulating device of the said type has a multiway valve that throttles in the intermediate positions as the speed set-point adjuster for each consumer, in which case the multiway valves assigned to the individual consumers are preferably switched together in the form of a block valve, where the adjusting element of the pump is controlled in the sense of a regulation of the stream required through the pressure drop at the restrictor of this multiway valve. In order to achieve a situation where each consumer moves with the desired speed independently of the load if several consumers are simultaneously controlled, where different pressures will always occur in the operating state in the individual consumers, a hydraulically controlled load-equalizing parallel-connection restrictor, which is acted upon by a control pressure whose level is determined by the pressure of the consumer operating with the highest pressure, is assigned to each consumer (European Patent 0,053,323). Very good results and functions can be achieved with such drive functions. However, the disadvantages are that the main working stream must necessarily flow through a restrictor in which a portion of the energy is annihilated and also that the hydraulic control pressure lines required necessitate a great expense.